Both reflective and nonreflective highway lane dividers and roadmarkers, of either plastic or glazed ceramic, have been known, and are typified by those disclosed in U.S. Pat. Nos. D 207,038, D 215,376 and D 225,087.
Generally, these roadmarkers are affixed to a pavement surface with a suitable, conventional all-weather adhesive, usually having an epoxy base.
However, due to the various lateral forces the roadmarker is subjected to over a period of protracted exposure to heavy traffic, aggravated by the surface irregularities which occur in various types of pavement, displacement, and consequential replacement, of roadmarkers has posed a rather expensive problem to date.
As disclosed in U.S. Pat. No. 3,499,371, it has been proposed to enhance adherence through the utilization of concentric ridges formed on the bottom of the roadmarker.
However, it has been found that such ridges can actually detract from bonding characteristics because of air entrapment and consequential discontinuity in the epoxy adhesive interface, thereby weakening the bond.
Too, simply cutting radial grooves through the concentric rings of U.S. Pat. No. 3,499,371 would not materially alleviate the problem, as might at first be expected.